Beneficial effects of mindfulness-based intervention on hippocampal volumes and episodic memory for childhood adversity survivors

An 8-week mindfulness-based intervention (MBI) led to increases in right hippocampus and right subiculum volumes among adults with adverse childhood experiences, while an active control condition (stress management education) did not. Only the MBI group improved pattern separation, a measure of episodic memory, and this improvement was linked to stress reduction and right subiculum volume changes. The findings indicate that mindfulness training may counteract some negative neural effects of early-life stress, with the subiculum playing a key role in reducing stress reactivity.

Study at a glance

Abstract

Background: Adverse Childhood Experience (ACE) has detrimental impacts on neural development, especially hippocampal morphometry. Mindfulness-Based Interventions (MBI) has been shown to induce adaptive hippocampal changes especially at the subiculum. The present study aims to investigate the effects of MBI on subiculum volumes among ACE survivors, as well as the effects on episodic memory as a probe into hippocampal functionality. Methods: We analyzed anatomical MRI data and performance indices from an episodic memory task called the Mnemonic Similarity Task (MST) collected from a randomized controlled longitudinal study that compared an 8-week MBI (N = 20) to an active control condition of Stress Management Education (SME) (N = 19). FreeSurfer 6.0 was used for automated hippocampal subfield segmentation and volumetric estimation. Results: Significant group differences were observed with the volumetric changes of the right whole hippocampus and right subiculum. Only the MBI group showed improved pattern separation capability from MST, which was associated with stress reduction and right subiculum volumetric changes. Limitations: Modest sample size. MST task was performed outside of MRI. Conclusions: These findings suggest beneficial effects of MBI for hippocampal volumes and episodic memory, while highlighting the importance of the subiculum for MBI-induced neural and cognitive changes. The subiculum's known role in inhibitory control was interpreted as a potential mechanism for it to exhibit MBI-induced volumetric changes, which sheds light on the potential neural underpinnings of mindfulness meditation for reducing stress reactivity among ACE survivors.